High‐performance reactive silver‐ion adsorption and reductive performance of poly(N‐methylaniline)

Abstract

Self-assembled poly(N-methylaniline) (PNMA) microspheres were prepared in a facile way by an unstirred polymerization of N-methylaniline monomers with ammonium persulfate as an oxidizing agent at different temperatures. The polymers were characterized by FTIR and UV-vis spectroscopy, SEM, TEM and wide-angle X-ray diffraction. Furthermore, adsorption property of PNMA microspheres for silver ions from aqueous solution was investigated by batch experiments. The results revealed that PNMA showed a high-performance adsorption for silver ions by chelation and redox reaction. The maximum adsorption capacity was up to 2.460 g/g for silver ions on PNMA microspheres prepared at 0°C, at an initial silver ion concentration of 160 mmol/L at 25°C for 48 hr. The adsorption process fits the pseudo-secondorder kinetics and Freundlich isotherm models. Moreover, the PNMA microspheres exbihit high reductive performances for Au(III) and Pd(II) ions. Therefore, the PNMA microspheres have great potential application in removal and recovery of metal ions from industrial wastewater. K E Y W O R D Sadsorption, high performance polymer, metal ions, redox polymer

Selective Reductive Removal of Silver Ions from Acidic Solutions by Redox-Active Covalent Organic Frameworks

“…Recently, covalent organic framework (COF) materials stood out as the most fascinating and popular crystalline porous materials. − The high porosity, physical and chemical stability, large surface area, and tunable functionality characteristics have endowed COF materials great potentials pertaining to diverse applications. ,,− In particular, the imine-linked COF, as one class of COF materials, formed via the co-condensation of amines and aldehydes groups, have also been widely used owing to their stronger structural stability and inherent chemical characteristic. − Further, the imine-linked COF materials contain abundant unsaturated amine groups at the edge of the COF structure, or as a linker fragment within the synthesis of COF. As reported in some references, − many amine groups (like amino and imino groups) are reducible. Metal nanoparticles were also reported to be highly stabilized on the COF surface due to their strong interaction with the N sites of the framework. , Therefore, it is potentially accessible for the redox-active COF in the selective removal and recovery of metal ions from an aqueous solution by chemical adsorption, rather than based on the commonly mentioned functional group complexation and physical adsorption. ,− …”

Removal behavior and mechanism of silver from low concentration wastewater using cellulose aerogel modified by thiosemicarbazide

“…For example, triethanolamine modified graphene oxide was used for the removal of silver ions by reduction-adsorption, 34 and poly(N-methylaniline) showed high adsorption and reductive performance to silver ions. 35 Hence, introducing functional group with reducing and adsorbing properties into the cellulose aerogels is an alternative to improve the removal efficiency of silver ions. Thiosemicarbazide modification has been widely used to enhance the removal efficiency of heavy metals such as Hg(II), 36 Ag(I), 37 Cu(II), 38 Pb(II), and Cd(II) 39 due to its simple process and effective performance.…”